JPH07208293A - Electromagnetic fuel injection valve - Google Patents

Abstract

PURPOSE:To provide an electromagnetic fuel injection valve, wherein its sliding property can be improved without deteriorating responsiveness in injection control and without increasing a manufacturing cost. CONSTITUTION:A fuel injection valve 1 is provided with a core 2, a nozzle 6 provided with a valve seat 6a and a fuel injection hole 6b, and a plunger rod 5. A rod 51 of the plunger rod 5 is provided with an upstream side guide part 51b to be slid in a hole 2a in the axial direction of the core 2, a valve body part 51a to sit on the valve seat 6a, and an intermediate part 51m, and the upstream side guide part, the valve body part, and the intermediate part 51m are made of the same nonmagnetic materials and integrally formed into one body. The upstream side guide part 51b and the intermediate part 51m are provided with notches. Moreover, a magnetic ring 52 of the plunger rod 5 is connected and fixed to the outer periphery of the intermediate part 51m.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetic fuel injection valve, and more particularly to an electromagnetic fuel injection valve suitable as a fuel injection valve used in a vehicle fuel supply system.

[0002]

2. Description of the Related Art Known technologies for electromagnetic fuel injection valves include:
For example: JP, 1-159460, A In this publicly known art, a plunger rod has a collision surface part between a ball and a stopper which constitute a valve body which has been subjected to high hardness quenching treatment and high precision processing to achieve oil tightness and durability. A shaft member welded and fixed to the ball, a plunger made of a magnetic material arranged to face the core in the axial direction and joined and fixed to one end of the shaft member, and one end joined and fixed to the inner diameter of the plunger. At the same time, the other end is inserted into the inner surface of the core and is constituted by a guide ring made of a non-magnetic material that serves as a guide for sliding. As a modified example of this, a guide ring and a plunger are hollow, and a known technology example in which one end of a spring that presses a plunger rod is housed in this hole, or about two in the vicinity of a fixed joint between a shaft member and a plunger. There is a known technique example in which the fuel passage is formed by providing the small holes.

[0003] A known technique is to integrate a shaft member and a plunger in a plunger rod having no guide ring, and the known technique is a plunger. A guide ring that serves as a sliding guide is fixed to one end of the
A technique is already known in which three known techniques are combined to form a plunger rod with three members including a ball, a shaft member and a plunger, and a sliding ring.

Japanese Patent Laid-Open No. 63-94069 discloses a known needle valve having a tip portion, a shaft member, and a rear end portion, which serves as a guide for sliding outside the core.
It has a large diameter portion at one place.

In this known technique, a slide mechanism is separately provided inside the core so that the plunger rod is directly inserted into the core and supported without sliding.

[0006]

However, the above-mentioned known techniques have the following problems. That is, in the known technique, the ball, the shaft member, the plunger (the above three are collectively referred to as a plunger rod hereafter), and the guide ring are all separate members, and in the known technique combining the known techniques, Are the same member, but these and the ball or the guide ring are separate members, and they are separately made and then fixedly coupled. Therefore, it is difficult to obtain a high coaxiality between the plunger rod and the guide ring because the error of each component accuracy and the error of the coupling accuracy are accumulated, and the accuracy is 10 in the economical mass production process. ~
The limit is about 100 μm. Therefore, it is difficult to obtain good sliding characteristics when the plunger rod reciprocates between the nozzle and the stopper, which is disadvantageous in improving the dynamic operation characteristics and durability of the electromagnetic fuel injection valve.

Further, in the known technique, it is necessary to make the span between the two large diameter portions large to some extent in order to stabilize the sliding characteristics, and the overall axial distance of the needle valve becomes long. That is, since the sliding portion becomes heavy, the response in injection control becomes poor. Further, the axial distance of the nozzle becomes long, which makes it difficult to perform precision machining of a hole having an elongated inner diameter in the nozzle, resulting in an increase in manufacturing cost.

Further, in the known art, since a slide mechanism different from the plunger rod is required, the number of parts is increased and the assembling work is complicated, resulting in an increase in manufacturing cost. Further, since the size of the inner diameter of the core is limited, there is an inconvenience in downsizing the fuel injection valve.

An object of the present invention is to provide an electromagnetic fuel injection valve capable of improving sliding characteristics without deteriorating responsiveness in injection control and increasing manufacturing cost.

[0010]

In order to achieve the above object, according to the present invention, a fixed iron core provided with an axial hole on a central axis, an electromagnetic coil for applying an electromagnetic force, and a valve seat are provided. A nozzle having a fuel injection hole, a slide guide inserted into an axial hole of the fixed iron core and sliding in the hole, a valve body portion seated on the valve seat, the sliding guide, and the valve. A plunger rod having an intermediate portion provided in the middle of the body portion and a movable iron core fixed to the outer periphery of the intermediate portion and facing the fixed iron core in the axial direction; and the electromagnetic coil to the movable iron core. In an electromagnetic fuel injection valve in which the plunger rod slides by applying an electromagnetic force to control the injection amount from the fuel injection hole, the plunger rod includes the sliding guide, the valve body portion, and the intermediate portion. Are all integrally formed from the same material Electromagnetic fuel injection valve is provided, characterized by being.

[0011] Preferably, in the electromagnetic fuel injection valve, there is provided an electromagnetic fuel injection valve characterized in that a front end portion and a rear end portion of the plunger rod are respectively supported through sliding guides. It

Further preferably, in the electromagnetic fuel injection valve, the plunger rod includes a first shaft portion provided between the sliding guide and the intermediate portion, the intermediate portion and the valve body portion. And a second shaft portion provided between the first and second shaft portions, the first shaft portion and the second shaft portion having the same outer diameter. Will be provided.

More preferably, in the electromagnetic fuel injection valve, there is provided the electromagnetic fuel injection valve, wherein the plunger rod has a convex portion for holding a spring for pressing the plunger rod.

Further, preferably, in the electromagnetic fuel injection valve, the movable iron core is made of a magnetic material, and the sliding guide, the valve body portion and the intermediate portion are made of a non-magnetic material. An electromagnetic fuel injection valve characterized by the above is provided.

More preferably, in the electromagnetic fuel injection valve, the non-magnetic material is one of non-magnetic stainless steel, non-magnetic sintered alloy, non-magnetic cermet, and non-magnetic ceramic. An electromagnetic fuel injection valve is provided.

Further preferably, in the electromagnetic fuel injection valve, at least one of the sliding guide and the intermediate portion has a cutout portion forming a communication hole that communicates the upstream side and the downstream side thereof. An electromagnetic fuel injection valve having the above is provided.

More preferably, in the electromagnetic fuel injection valve, two cutout portions are provided in at least one of the slide guide and the intermediate portion,
Further, there is provided the electromagnetic fuel injection valve, wherein the two cutout portions are two flat surfaces facing each other in the axial direction in parallel with each other.

Further, preferably, in the electromagnetic fuel injection valve, two notches are provided in at least one of the slide guide and the intermediate portion, and each notch is provided. Provided is an electromagnetic fuel injection valve, which has a substantially semicircular shape in a radial cross section, and is provided so as to face the center axis in the cross section.

More preferably, in the electromagnetic fuel injection valve, three notches are provided in at least one of the slide guide and the intermediate portion,
In addition, each notch has a substantially semicircular shape in the radial cross section, and the circumferential positions in the cross section are arranged so as to be spaced by 120 ° from each other at an angle from the central axis. A featured electromagnetic fuel injection valve is provided.

Further, preferably, in the electromagnetic fuel injection valve, the sliding guide is in contact with the axial hole of the fixed iron core through a drum-shaped sliding surface which is a curved surface convex in the axial direction. An electromagnetic fuel injection valve is provided.

More preferably, in the electromagnetic fuel injection valve, there is provided the electromagnetic fuel injection valve, wherein the plunger rod has a concave portion for holding a spring for pressing the plunger rod.

Further, preferably, in the electromagnetic fuel injection valve, the sliding guide is provided on the valve body portion side end surface, the intermediate portion of the valve body portion side end surface, and the valve body portion on the fixed core side. Provided is an electromagnetic fuel injection valve, wherein at least one of the end faces of the collision plate facing the stopper is formed on a face having a gradient in the radial direction of the plunger rod. .

More preferably, in the electromagnetic fuel injection valve, the end surface of the sliding guide on the valve body side is formed into a surface having a gradient in the radial direction of the plunger rod. A fuel injection valve is provided.

Further, preferably, in the electromagnetic fuel injection valve, an end surface of the intermediate portion on the valve body portion side is formed into a surface having a gradient in a radial direction of the plunger rod. A fuel injection valve is provided.

More preferably, in the electromagnetic fuel injection valve, the end face of the collision plate, which is provided on the fixed core side of the valve body and is in contact with the stopper, is inclined in the radial direction of the plunger rod. There is provided an electromagnetic fuel injection valve, which is characterized in that it is formed on a surface having.

[0026]

In the present invention constructed as described above, since the sliding guide of the plunger rod, the valve body portion and the intermediate portion are all integrally formed of the same material, the coaxial precision of them is reduced to one component. It can be determined by the processing accuracy of. In general, precision machining of such elongated shaft parts is relatively easy, and by using a centerless grinder, for example, it is possible to perform highly efficient and highly productive machining.
With respect to the coaxiality between the valve body portion and the sliding guide, an accuracy of about 1 to 5 μm can be relatively easily obtained. That is, since the coaxiality can be improved as compared with the related art in which another member is coupled, the sliding characteristic of the plunger rod can be improved. At this time, the sliding guide is inserted into the axial hole of the fixed iron core and slides in the hole to provide two large-diameter portions, which serve as sliding guides, outside the fixed iron core as in the prior art. Since it is not necessary to take a large span, the sliding part does not become heavy and the responsiveness does not deteriorate. In addition, the manufacturing cost does not increase due to the necessity of machining the fine pores of the nozzle. Further, unlike the prior art in which the slide mechanism is provided, the number of parts is not increased and the assembly work is not complicated and the manufacturing cost is not increased.

Further, since the front end portion and the rear end portion of the plunger rod are respectively supported through the slide guides, good sliding characteristics can be surely maintained by the two-point support. Further, since the first shaft portion between the sliding guide and the intermediate portion and the second shaft portion between the intermediate portion and the valve body portion have the same outer diameter, the centerless grinding machine can During processing, the processing accuracy of the plunger rod (particularly roundness and coaxiality) is further improved. Further, by adopting a structure in which the spring for pressing the plunger rod is held by the convex portion, the convex portion can be simultaneously processed in the centerless grinding process, and the manufacturing process can be reduced. Furthermore, by constructing the sliding guide, the valve body, and the intermediate portion with a non-magnetic material, it is possible to prevent the sliding guide from being attracted to the inner surface of the fixed iron core and deteriorating the sliding characteristics, while being movable. By using the iron core as a separate member from these, it is possible to use a soft material such as a permalloy material having extremely good magnetic characteristics. Also, by using non-magnetic stainless steel, non-magnetic sintered alloy, non-magnetic cermet and non-magnetic ceramic as the non-magnetic material, the seating surface of the valve body, the collision surface of the collision plate, the wear resistance of the sliding guide and The durability can be improved. Furthermore, by forming a communication hole that communicates the upstream side and the downstream side by the notch provided in at least one of the sliding guide and the intermediate portion,
It is possible to prevent fuel pools from being generated inside the fixed core when the plunger rod slides. Further, since the contact area with the inner surface of the hole of the fixed iron core in the axial direction is reduced, the sliding resistance can be further reduced and the variation in the sliding resistance can be suppressed to an extremely small value. Further, as compared with the case where the fuel passage is formed by providing about two small holes as in the conventional example, the notch is formed, the machining efficiency is faster, the deburring is easier, and the labor of the machining can be reduced. Furthermore, it can be adopted for a top-feed type injection valve without separately making small holes for fuel passage. Further, as an example of the configuration of the cutout portion, two flat surfaces facing each other in parallel to each other in the axial direction can be used. Further, the shape in the radial cross section may be two substantially semicircular shapes that face each other with the central axis sandwiched therebetween, and in this case, a configuration that is advantageous in terms of support accuracy against tilting in the direction perpendicular to the axis can be obtained. Further, the amount of fuel that can pass can be increased. Further, in the radial cross section, three substantially semicircular shapes can be formed in which the circumferential positions are arranged at an angle of 120 ° with respect to the central axis, and in this case, in the case of tilting in the direction perpendicular to the axis, Therefore, the structure can be made more advantageous in terms of supporting accuracy. Further, the amount of fuel that can pass can be further increased. Further, since the sliding guide comes into contact with the axial hole through the drum-shaped sliding surface, the contact area with the inner surface of the hole is reduced, so the sliding resistance can be further reduced, and the variation in sliding resistance can be reduced. It can be kept extremely small. Further, by holding the spring that presses the plunger rod in the concave portion, the axial length of the entire plunger rod and spring can be made smaller.

Further, since the end surface of the sliding guide on the valve body side, the end surface of the intermediate portion on the valve body side, and the end surface of the collision plate facing the stopper on the valve body side are formed to have a radial gradient surface. When processing the end surface on the opposite side of these end surfaces to a surface perpendicular to the axis, an angular centerless grinding machine can be used, and the radial surface can be processed with high accuracy.

[0029]

Embodiments of the present invention will be described below with reference to FIGS.

A first embodiment of the present invention will be described with reference to FIGS. The electromagnetic fuel injection valve of this embodiment is shown in FIG.
In FIG. 1, a fuel injection valve 1 includes a core 2 made of a magnetic material and provided with an axial hole 2a on a central axis, and an electromagnetic coil 3 arranged concentrically with the core 2 to apply an electromagnetic force.
And a yoke 4 that covers the outer circumference of the electromagnetic coil 3 and forms a magnetic circuit with the core 2, a nozzle 6 having a valve seat 6a and a fuel injection hole 6b, and a plunger rod 5.

The detailed structure of the plunger rod 5 is shown in FIG. 1 and 2, the plunger rod 5 includes a rod 51 arranged coaxially with the core 2 and a magnetic ring 52 axially opposed to the core 2 via an air gap.
It has and. The rod 51 is a hole 2 in the axial direction of the core 2.
upstream guide part 5 inserted in a and sliding in the hole 2a
1b, a valve body portion 51a seated on the valve seat 6a, an intermediate portion 51m provided between the upstream guide portion 51b and the valve body portion 51a, and an upstream guide portion 51b and an intermediate portion 51m. It has a shaft portion 51i provided, a shaft portion 51n provided between the intermediate portion 51m and the valve body portion 51a, and a collision plate 51e that is in contact with the stopper 7 provided in the nozzle 6. These are all integrally formed of the same material. As this material, a material obtained by drawing a non-magnetic stainless steel to give a working strain and hardening the non-magnetic stainless steel is used, and is mainly manufactured by precision working using a grinding working method. The outer diameter D ₁ of the shaft portion 51n and the outer diameter D ₂ of the shaft portion 51ι are the same (see FIG. 6 described later).

The upstream guide portion 51b of the rod 51
Are two notch parts 51f, which form the communication holes 17, 17 that connect the upstream side and the downstream side of the upstream guide part 51b.
It has 51f. The intermediate portion 51m of the rod 51 has a communication hole 18, which connects the upstream side and the downstream side of the intermediate portion 51m.
It has two notch parts 51g, 51g forming 18. The cutouts 51f, 51f and 51g, 51g are two planes facing each other in the axial direction in parallel with each other. A view of the cutout portions 51f, 51f viewed from the X direction is shown in FIG.

Further upstream of the rod 51 (upper side in FIG. 1)
The end portion is provided with a convex spring support portion 51c. This is shown in FIG. In FIG. 4, the spring support portion 51c of the rod 51 holds the spring 8,
The spring 8 engages with the spring support portion 51 and presses the plunger rod 5 downstream (downward in FIG. 1).

The magnetic ring 52 is made of a magnetic material and is fixedly connected to the outer periphery of the intermediate portion 51m of the rod 51. This combining method will be described with reference to FIG. In FIG. 5, the hollow magnetic ring 52 is arranged in the restraining jig 13 installed on the receiving jig 14, and the rod 51 is inserted into the magnetic ring 52. Thereafter, the inner diameter side end surface 52a of the magnetic ring 52 is pressed by the punch 12 to slightly deform the magnetic material forming the magnetic ring 52 to give a restraining force in the inner diameter direction.
The intermediate portion 51m and the magnetic ring 52 are fixedly coupled. Other than this, there is also a method of fixing the intermediate portion 51m and the magnetic ring 52 by laser welding or the like.

Further, in FIG. 1, the valve guide 61 arranged in the nozzle 6 comes into contact with the outer peripheral portion of the valve body 51a and serves as a guide for sliding the valve body 51a.
Is provided.

In the above structure, the plunger rod 5 slides between the nozzle 6 and the stopper 7 due to the electromagnetic force applied to the magnetic ring 52 by the electromagnetic coil 3 and the spring force applied to the spring support portion 51c by the spring 8. Thus, the injection amount from the fuel injection hole 6b is controlled.

According to the present embodiment configured as described above,
Since the upstream guide portion 51b, the valve body portion 51a, and the intermediate portion 51m of the rod 51 are all integrally formed of the same material, their coaxial precision can be determined by the machining precision of one component. In general, precision machining of such an elongated shaft component is relatively easy. For example, by using a centerless grinder or the like, it is possible to perform machining with high efficiency and high mass productivity. Part 51b
An accuracy of about 1 to 5 μm can be obtained relatively easily in terms of coaxiality with. That is, since the coaxiality can be improved as compared with the related art in which another member is coupled, the sliding characteristic of the plunger rod 5 can be improved.
Therefore, the dynamic operation characteristic of the fuel injection valve 1 is improved. In addition, at this time, the upstream guide portion 51b is arranged so that the axial direction hole 2 of the core 2 is
Since it is inserted in a and slides in the hole 2a, it is not necessary to have a large span as in the prior art in which two large diameter portions serving as guides for sliding are provided outside the core, and the sliding portion becomes heavy. The responsiveness does not deteriorate. In addition, the manufacturing cost does not increase due to the necessity of machining the fine pores of the nozzle. Further, unlike the prior art in which the slide mechanism is provided, the number of parts is not increased and the assembly work is not complicated and the manufacturing cost is not increased.

Further, the downstream guide portion 16 provided on the nozzle 6 comes into contact with the outer peripheral portion of the valve body portion 51a, so that the valve body portion 51a.
Since it serves as a guide for the sliding, it is possible to reliably maintain good sliding characteristics by the two-point support with the upstream guide portion 51b. Further, the upstream guide portion 51b and the intermediate portion 51
Since the outer diameter D ₂ of the shaft portion 51ι between the shaft 51m and m is the same as the outer diameter D ₁ of the shaft portion 51n between the intermediate portion 51m and the valve body portion 51a, the rod 51 is processed by the centerless grinding machine. In this case, in the adjusting wheel 10 (see FIG. 6) which is arranged so as to face the grindstone 11 with the bar material being a material therebetween, the surface 1 corresponding to the shaft portion 51n and the shaft portion 51ι of the rod 51.
Since the peripheral velocities at 0n and 10ι are equal, slippage does not occur between the shaft portions 51n and 51ι and the surfaces 10n and 10ι. Therefore, the grinding process is facilitated, and the processing accuracy of the rod 51 (particularly the circularity and the coaxiality) is further improved, and the variation in accuracy among products is reduced. In addition, highly efficient production is possible without being affected by the external dimension error of the material and a slight bending. In addition, the convex spring support portion 5
Since the spring 8 for pressing the plunger rod 5 is held by 1c, the spring support portion 51c can be simultaneously processed in the centerless grinding process, and the manufacturing process can be reduced. Therefore, the manufacturing cost can be reduced. Further, since the upstream guide portion 51b is made of a non-magnetic material, it is possible to prevent the upstream guide portion 51b from being attracted to the inner surface of the core 2 and deteriorating the sliding characteristics, while the magnetic ring 52 is connected to these. By using a separate member, it is possible to use a soft material such as a permalloy material having extremely good magnetic characteristics. Therefore, the dynamic fuel injection characteristic of the fuel injection valve 1 is improved. Further, since non-magnetic stainless steel is used as this non-magnetic material, the seating surface of the valve body portion 51a on the valve seat 6a, the collision surface of the collision plate 51e on the stopper 7, and the wear resistance and durability of the upstream guide portion 51b. It is possible to improve the sex. Therefore, it is possible to extend the product life by minimizing the change in characteristics of the injection valve 1 with time. Furthermore, since a material obtained by drawing and hardening non-magnetic stainless steel to give work strain is used, the induction hardening work and the annealing work of the welded part and the hardened part are unnecessary, and the manufacturing cost can be reduced accordingly. Further, the cutout portions 51f, 51f of the upstream guide portion 51b and the cutout portions 51g, 5 of the intermediate portion 51m.
Communication hole 17, which connects the upstream side and the downstream side by 1 g,
Since 17 and 18, 18 are formed, it is possible to prevent fuel pools from being generated inside the core 2 when the plunger rod 5 slides, and prevent deterioration of sliding characteristics. Further, since the contact area with the inner surface of the hole 2a in the axial direction of the core 2 is reduced, the sliding resistance can be further reduced, and the variation in the sliding resistance can be suppressed to a very small level. Therefore, it is possible to reduce variations in dynamic fuel injection characteristics among products. It can also be used in a top-feed type injection valve without separately drilling small holes for fuel passage.

In the above embodiment, the rod 51
Although non-magnetic stainless steel was used as the material of (1), other non-magnetic materials (non-magnetic sintered alloy, non-magnetic cermet, non-magnetic ceramic, etc.) may be used, and the same effect is obtained in this case.

A second embodiment of the present invention will be described with reference to FIG. This embodiment is an embodiment of an electromagnetic fuel injection valve having cutouts of different shapes in the upstream guide portion and the intermediate portion of the rod. FIG. 7 shows notches 251f, 251f provided in the upstream guide portion 251b of the rod 251 of the electromagnetic fuel injection valve of this embodiment. Members common to the first embodiment are designated by common reference numerals. In FIG. 7, the notch portions 251f and 251f of this embodiment differ from the notch portions 51f and 51f (see FIG. 3) of the first embodiment in that the shape in the radial cross section (that is, FIG. 7) is substantially different. It is a semicircular shape. The cutout portions 251f, 251f are provided so as to face each other with the central axis interposed therebetween. Further, a notch portion having a similar radial cross-sectional shape is also provided in the intermediate portion (not shown). The other points are almost the same as in the first embodiment.

According to this embodiment, in addition to the effects of the first embodiment, the plunger rod 5 (in the Y direction in the figure)
It is possible to further improve the support accuracy against the flare. Further, the amount of fuel that can pass can be increased.

A third embodiment of the present invention will be described with reference to FIG. This embodiment is also an embodiment of the electromagnetic fuel injection valve provided with the cutout portions having different shapes in the upstream guide portion and the intermediate portion of the rod. FIG. 8 shows notches 351f, 351f, 351f provided in the upstream guide portion 351b of the rod 351 of the electromagnetic fuel injection valve of this embodiment. Members common to the first and second embodiments are designated by common reference numerals. In FIG. 8, the notch portions 351f, 3 of this embodiment
51f and 351f are cutout portions 251f and 251f of the second embodiment.
The difference from 251f is that three upstream guide portions 351f are provided, and that the circumferential positions in each radial cross section (that is, FIG. 8) are 120 ° apart from each other in the angle from the central axis. It is arranged. Further, a notch portion having a similar radial cross-sectional shape is also provided in the intermediate portion (not shown). Other points are the second
This is almost the same as the embodiment described above.

According to this embodiment, it is more advantageous in terms of supporting accuracy than the structure of the second embodiment shown in FIG. 7 against the deflection of the plunger rod 5 (in the Y direction in the drawing). Further, the amount of fuel that can pass can be further increased.

Although the cutouts 251f and 351f are formed in a semi-circular shape in the second and third embodiments above, the shape is not limited to this and may be, for example, a substantially circular shape. Get the same effect.

A fourth embodiment of the present invention will be described with reference to FIG. This embodiment relates to a plunger rod having a different shape applicable to a side-feed type electromagnetic fuel injection valve. FIG. 9 shows the detailed structure of the plunger rod 405 of the electromagnetic fuel injection valve of this embodiment. Members common to those of the first to third embodiments are designated by common reference numerals. Figure 9
2, the plunger rod 405 of the present embodiment is different from the plunger rod 5 of the first embodiment (see FIG. 2) in that the upstream guide portion 451b and the intermediate portion 451m of the rod 451 are not provided with cutout portions. That is.
The other points are almost the same as in the first embodiment.

In the above, the above structure is adopted for a side-feed type injection valve and a structure for preventing fuel from accumulating inside the core 2. In this case, the sliding characteristics of the plunger rod 405 do not deteriorate even if the notch is not provided. Therefore, as compared with the first to third embodiments, the manufacturing process can be reduced because the machining of the notch is unnecessary, so that the manufacturing cost can be reduced.

The fifth embodiment of the present invention is shown in FIGS.
Will be described. The present embodiment is an embodiment of an electromagnetic fuel injection valve provided with rods having different shapes of the upstream guide portion and the intermediate portion. FIG. 10 shows the detailed structure of the plunger rod 505 of the electromagnetic fuel injection valve of this embodiment. Members common to those of the first to fourth embodiments are designated by common reference numerals. Figure 1
0, the plunger rod 505 of the present embodiment is the fourth
9 is different from the plunger rod 405 (see FIG. 9) of the first embodiment in that the upstream guide portion 551b of the rod 551 has an hourglass-shaped sliding surface 551p that is a curved surface that is convex in the axial direction. Axial hole 2 of core 2 through moving surface 551p
That is, the magnetic ring 52 and the intermediate portion 551m are firmly fixed by using the thin V groove 551d cut in the intermediate portion 551m of the rod 551. The other points are almost the same as in the fourth embodiment.

FIG. 11 shows a method of coupling and fixing the intermediate portion 551m of the rod 551 and the magnetic ring 52. The same members as those in FIG. 5 of the first embodiment are designated by the same reference numerals. Figure 11
In, the joining method in the first embodiment (see FIG. 5)
The difference from the above is, for example, as shown in Japanese Patent Laid-Open No. 63-111280, a thin V is formed on the outer periphery of the intermediate portion 551m.
The groove 551d is cut, and the inner diameter side end surface 52a of the magnetic ring 52 is cut.
Is pressed to slightly deform the material, and the material is fitted into the V groove 551d.
It is to fix and. The other points are almost the same as in the first embodiment.

According to this embodiment, the upstream guide portion 551
Since the portion b contacts the axial hole 2a of the core 2 through the drum-shaped sliding surface 551p, the contact area with the inner surface of the hole 2a is reduced, so that the sliding resistance can be further reduced and the sliding resistance can be reduced. It is possible to suppress the variation in the value to be extremely small. Therefore, it is possible to reduce variations in dynamic fuel injection characteristics among products. Further, the material of the magnetic ring 52 is slightly deformed, and the V groove 551 cut in the intermediate portion 551m.
The rod 551 and the magnetic ring 5
2 can be more firmly bonded and fixed.

The structure of the V groove 551d and the structure of the sliding surface 551p of this embodiment can be applied to the fuel injection valves of the first to fourth embodiments, and the same effect can be obtained in this case as well. .

A sixth embodiment of the present invention will be described with reference to FIG. The present embodiment is an embodiment of an electromagnetic fuel injection valve having upstream guide portions of different shapes. FIG. 12 shows the structure of the upstream guide portion 651b of the electromagnetic fuel injection valve of this embodiment. Members common to the first to fifth embodiments are designated by common reference numerals. In FIG. 12, the rod 65 of this embodiment is
1 is different from the upstream guide portion 51b of the first embodiment (see FIG. 4) in that a concave spring support portion 651c holding the spring 8 pressing the plunger rod 605 is provided. It is that you are.
The other points are similar to those of the first embodiment.

According to this embodiment, since the spring 8 is held by the concave spring support portion 651c, the axial length of the plunger rod 605 and the spring 8 as a whole can be made smaller. Therefore, it is particularly suitable when the axial length of the plunger rod 605 is limited.

The seventh embodiment of the present invention will be described with reference to FIG. The present embodiment is an embodiment of an electromagnetic fuel injection valve provided with a rod having a shape that enables highly accurate processing. A method of processing the rod 751 of the electromagnetic fuel injection valve of this embodiment will be described with reference to FIG.
3 shows. 13, the rod 751 of this embodiment is different from the rod 51 of the first embodiment (see FIG. 6) in that
An end face 751j on the valve body 751a side (left side in the drawing) of the upstream guide portion 751b and a valve body 751 of the intermediate portion 751m.
The end face 751i on the a side and the valve body portion 7 of the collision plate 751e provided on the core 2 side of the valve body portion 751a and in contact with the stopper 7
The end surface 751h on the 51a side is formed as a surface having a gradient in the radial direction of the rod 751, and the grindstone 711 is inclined with respect to the radial direction of the rod 751 by processing using an angular type centerless grinder. That is, it is cut (see the arrow in the figure). The other points are similar to those of the first embodiment.

According to this embodiment, the upstream guide portion 751
end surface 751j of b and end surface 751i of intermediate portion 751m
And the end surface 751h of the valve body portion 751a, the rod 751
Is formed on a surface having a gradient in the radial direction, the end surface on the opposite side of these end surfaces, that is, the upstream guide portion 75.
1b, the end surface 751k on the core 2 side (right side in the figure), the end surface 751q on the core 2 side of the intermediate portion 751m, and the valve body portion 751a.
When processing the end surface 751r of the collision plate 751e on the core 2 side into a surface perpendicular to the axial direction, an angular type centerless grinding machine can be used. Therefore, the end faces in the radial direction can be processed with higher accuracy.
Therefore, the post-processing can be omitted again and the manufacturing cost can be reduced. In the above embodiment, the end surface 751j of the upstream guide portion 751b, the end surface 751i of the intermediate portion 751m, and the end surface 751h of the valve body portion 751a are all formed into a surface having a gradient in the radial direction of the rod 751. However, if at least one of the above three is formed on a surface having a gradient in the radial direction, an angular centerless grinding machine can be used for that portion, and the above high precision machining can be performed. The effect can be obtained.

[0055]

According to the present invention, since the sliding guide of the plunger rod, the valve body portion and the intermediate portion are all integrally formed of the same material, they are coaxial as compared with the prior art in which separate members are joined. It is possible to improve the sex. Therefore, the sliding characteristics of the plunger rod can be improved, and the dynamic operation characteristics of the electromagnetic fuel injection valve can be improved. At this time, the sliding guide is inserted into the axial hole of the fixed iron core and slides in the hole, so the sliding part does not become heavy and the responsiveness does not deteriorate. The manufacturing cost does not increase due to the processing. further,
Unlike the prior art in which the slide mechanism is provided, the number of parts is not increased and the assembly work is not complicated and the manufacturing cost is not increased.

[Brief description of drawings]

FIG. 1 is an overall structural diagram of an electromagnetic fuel injection valve according to a first embodiment of the present invention.

FIG. 2 is a detailed structural diagram of a plunger rod.

FIG. 3 is a view showing a cutout portion of an upstream guide portion.

FIG. 4 is a structural diagram of a spring support portion.

FIG. 5 is a diagram showing a method of connecting a magnetic ring and a rod.

FIG. 6 is a view showing a state where a rod is processed by a centerless grinding machine.

FIG. 7 is a diagram showing a cutout portion provided in an upstream guide portion of an electromagnetic fuel injection valve according to a second embodiment of the present invention.

FIG. 8 is a view showing a notch portion provided in an upstream guide portion of an electromagnetic fuel injection valve according to a third embodiment of the present invention.

FIG. 9 is a detailed structural diagram of a plunger rod of an electromagnetic fuel injection valve according to a fourth embodiment of the present invention.

FIG. 10 is a detailed structural diagram of a plunger rod of an electromagnetic fuel injection valve according to a fifth embodiment of the present invention.

FIG. 11 is a diagram showing a method of connecting a magnetic ring and a rod.

FIG. 12 is a structural diagram of an upstream guide portion of an electromagnetic fuel injection valve according to a sixth embodiment of the present invention.

FIG. 13 is a diagram showing a method of processing a rod of an electromagnetic fuel injection valve according to a seventh embodiment of the present invention.

[Explanation of symbols]

 1 Fuel Injection Valve 2 Core (Fixed Iron Core) 2a Hole 3 Electromagnetic Coil 5 Plunger Rod 6 Nozzle 6a Valve Seat 6b Fuel Injection Hole 7 Stopper 8 Spring 16 Downstream Guide (Sliding Guide) 17 Communication Hole 18 Communication Hole 51a Valve Body Part 51b Upstream guide part (sliding guide) 51c Spring support part (convex part) 51e Collision plate 51f Cutout part 51ι Shaft part (first shaft part) 51m Intermediate part 51n Shaft part (second shaft part) 52 magnetic ring (movable iron core) 61 valve guide (sliding guide) 251b upstream guide part (sliding guide) 251f notch part 351b upstream guide part (sliding guide) 351f notch part 405 plunger rod 451b upstream guide Part (sliding guide) 451m intermediate part 505 plunger rod 551b upstream guide part ( Motion guide) 551m Intermediate part 551p Sliding surface 605 Plunger rod 651b Upstream guide part (sliding guide) 651c Spring support part (concave part) 751h End face (end face of valve body part of collision plate) 751i End face (valve of intermediate part) Body side end surface) 751j End surface (valve body side end surface of the first sliding portion)

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Masami Masuda, inventor Masami Masuda, 292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa, Ltd., Production Engineering Research Laboratory, Hitachi, Ltd. Inside Hitachi, Ltd. (72) Inventor Mikio Osugi 2520, Takaba, Katsuta-shi, Ibaraki Hitachi, Ltd. Automotive Equipment Division (72) Inventor Atsushi Sekine 2477 Kashima Yatsu, Katsuta, Ibaraki 3 Hitachi 3 Hitachi Automotive Engineering Co., Ltd. (72) Inventor Naobu Kanemaru 2520 Takaba, Katsuta-shi, Ibaraki Hitachi Ltd. Automotive Equipment Division (72) Inventor Kazuyoshi Terakado 2520 Takaba, Katsuta-shi, Ibaraki Hitachi Ltd. Automotive Equipment Division (72) Inventor Yoshiyuki Tanabe Ibaraki Affairs Oaza high field 2520 address Hitachi, Ltd. Automotive Equipment Division in the

Claims (16)

[Claims] 1. A fixed iron core having an axial hole formed on a central axis, an electromagnetic coil for applying an electromagnetic force, a nozzle having a valve seat and a fuel injection hole, and an axial hole of the fixed iron core. A slide guide that is inserted into the hole and slides in the hole, a valve body portion that sits on the valve seat, an intermediate portion that is provided between the sliding guide and the valve body portion, and an outer periphery of the intermediate portion. A plunger rod having a fixed iron core and a movable iron core axially opposed to the fixed iron core, wherein the plunger rod slides by applying an electromagnetic force to the movable iron core by the electromagnetic coil, In the electromagnetic fuel injection valve for controlling the injection amount of, the plunger rod is an electromagnetic fuel injection valve in which the sliding guide, the valve body portion and the intermediate portion are all integrally formed of the same material. Fuel injection valve. 2. The electromagnetic fuel injection valve according to claim 1, wherein a front end portion and a rear end portion of the plunger rod are supported by sliding guides, respectively. . 3. The electromagnetic fuel injection valve according to claim 1, wherein the plunger rod has a first shaft portion provided between the sliding guide and the intermediate portion, and the intermediate portion. An electromagnetic wave having a second shaft portion provided between the valve body portion and the first shaft portion and the second shaft portion having the same outer diameter. Type fuel injection valve. 4. The electromagnetic fuel injection valve according to claim 1 or 2, wherein the plunger rod has a convex portion that holds a spring that presses the plunger rod. 5. The electromagnetic fuel injection valve according to claim 1, wherein the movable iron core is made of a magnetic material,
The electromagnetic fuel injection valve, wherein the sliding guide, the valve body portion and the intermediate portion are made of a non-magnetic material. 6. The electromagnetic fuel injection valve according to claim 5, wherein the non-magnetic material is one of non-magnetic stainless steel, non-magnetic sintered alloy, non-magnetic cermet, and non-magnetic ceramic. Electromagnetic fuel injection valve characterized by. 7. The electromagnetic fuel injection valve according to claim 1 or 2, wherein at least one of the sliding guide and the intermediate portion forms a communication hole that communicates the upstream side and the downstream side thereof. An electromagnetic fuel injection valve having a cutout portion. 8. The electromagnetic fuel injection valve according to claim 7, wherein two notches are provided in at least one of the sliding guide and the intermediate portion, and the two notches are provided. The part is two planes that face each other in the axial direction in parallel with each other, and the electromagnetic fuel injection valve. 9. The electromagnetic fuel injection valve according to claim 7, wherein two notches are provided in at least one of the sliding guide and the intermediate portion, and
An electromagnetic fuel injection valve, wherein each notch has a substantially semicircular shape in a radial cross section, and is provided to face each other across the central axis in the cross section. 10. The electromagnetic fuel injection valve according to claim 7, wherein three notches are provided in at least one of the sliding guide and the intermediate portion, and each notch is provided. The portions have a substantially semicircular shape in a radial cross section, and are arranged so that their circumferential positions in the cross section are spaced by 120 ° from each other at an angle from the central axis. Injection valve. 11. The electromagnetic fuel injection valve according to claim 1, wherein the sliding guide is provided with a drum-shaped sliding surface that is a curved surface that is convex in the axial direction. An electromagnetic fuel injection valve, which is in contact with an axial hole of the fixed iron core. 12. The electromagnetic fuel injection valve according to claim 1 or 2, wherein the plunger rod has a concave portion that holds a spring that presses the plunger rod. 13. The electromagnetic fuel injection valve according to claim 1, wherein the end surface of the sliding guide on the valve body portion side, the end surface of the intermediate portion on the valve body portion side, and the fixing of the valve body portion. An electromagnetic fuel injection valve characterized in that at least one of the end surfaces of the collision plate, which is provided on the iron core side and is in contact with a stopper, is formed on a surface having a gradient in the radial direction of the plunger rod. . 14. The electromagnetic fuel injection valve according to claim 13, wherein an end surface of the sliding guide on the valve body portion side is formed into a surface having a gradient in a radial direction of the plunger rod. Electromagnetic fuel injection valve. 15. The electromagnetic fuel injection valve according to claim 13, wherein the end surface of the intermediate portion on the valve body portion side is formed into a surface having a gradient in the radial direction of the plunger rod. Electromagnetic fuel injection valve. 16. The electromagnetic fuel injection valve according to claim 13, wherein an end face of the collision plate, which is provided on the fixed iron core side of the valve body portion and is in contact with a stopper, is on the valve body portion side in a radial direction of the plunger rod. An electromagnetic fuel injection valve, characterized in that the electromagnetic fuel injection valve is formed on a surface having a gradient.